Graphical display techniques have been used on computers allowing the simulation of models of a concrete or abstract entity. The purpose of a model is to allow the user to visualize and understand the structure or behavior of the entity. A computer model, thereby, provides a convenient vehicle for experimentation with and prediction of the effects of inputs or modifications to the model. In particular, geometric models are well suited for graphical computer modeling. This is due to the fact that geometric models describe components with inherent geometrical properties which lend themselves easily to graphical representations. As can be expected, there are many aspects inherent with graphical geometric computer modeling. Among these are geometrical transformations, viewing in three dimensions, user interfacing, representing curves and surfaces, solid modeling, illumination, shading, visible-surface determination, image manipulation, etc.
The present invention is directed to one problem associated with graphical geometric computer modeling. The present invention is directed towards displaying the collision between two objects. In the past, collision detection was done by testing every edge/surface of the first object against every edge/surface of the second object and testing for inclusion. Then, this process is repeated in its entirety with the objects being reversed (i.e. testing every edge/surface of the second object against every edge/surface of the first object and testing for inclusion). For detailed collision detection, one would need to factor in the individual polygon or any curved surfaces of the objects. This traditional method for detecting collisions is very tedious and time consuming and thus, displaying the results of collisions takes a long time as the computations delay the final resulting display. What is needed is a faster, more efficient method for detecting collisions and then displaying the results of whether or not collisions have occurred.
One of the limitations of the prior art is that velocity effects are often ignored. The prior techniques typically test for collision in one frame and then test for collision in a subsequent, later frame. If there are no collisions detected in either frame, the prior techniques assume that there were no collisions in between the two frames. However, this assumption can sometimes be erroneous. One remedy is to take incrementally smaller time steps in between frames and testing for collisions within the closely spaced time frames. Again, this process is very tedious and time consuming. What is needed is an apparatus/method for displaying whether two objects which had been moved have collided or not at any point of their movement.